Abstract: Flatness actuators such as work roll bending and roll tilting can be fully utilized to regulate flatness error by using closed-loop feedback control system based on multivariable optimization algorithm model. The aim of closed-loop feedback is to maintain flatness consistency between measured value and set value. The system can fully use input information and consider functions between multiple flatness actuators, avoiding adverse effects among each other. Therefore, optimization algorithm program is a key to accurately calculate the adjustments of actuators. In order to build cold strip production line with domestic intellectual property, closed-loop feedback control system of 1 700 mm four stands four-high tandem cold rolling mill is studied thoroughly. Dual method is used to develop multivariable optimization algorithm program in C language, which is embedded in programmable logic controller(PLC). Closed-loop feedback control module with domestic intellectual property is developed. The results derived from the module of actuators adjustment and quadratic form optimum function Quadprog in Matlab toolbox show good agreement and high accuracy.

Key words: Closed-loop feedback control, Cold strip rolling, Dual method, Optimization algorithm